Method and apparatus for porous insulative film for insulating energy source layers

ABSTRACT

The present subject matter includes an apparatus, having: an anode having an elongate ribbon shape; a cathode having an elongate ribbon shape, the cathode disposed adjacent to and in alignment with the anode; a separator disposed between the anode and the cathode; and a first porous edge film disposed between a first edge of the cathode and the anode, with the one or more surfaces of the first porous edge film facing the cathode and defining a first cathode interface of the first porous edge film; wherein an first adhesive interconnects the first porous edge film to the cathode, the first adhesive covering less than the entire cathode interface, and the anode and cathode are disposed in a case with an electrolyte.

CROSS REFERENCE TO RELATED APPLICATIONS

The following commonly assigned U.S. patent is related to the presentapplication and is incorporated herein by reference in its entirety:“Flat Capacitor for an Implantable Medical Device,” U.S. Pat. No.6,699,265, filed November 3, 2000, issued Mar. 2, 2004. The presentapplication is related to the following commonly assigned U.S. PatentPublications which are incorporated herein by reference in theirentirety: “Method and Apparatus for Single High Voltage AluminumCapacitor Design,” Ser. No. 60/588,905, filed on Jul. 16, 2004;“Batteries Including a Flat Plate Design,” Ser. No. 10/360,551 filedFeb. 7, 2003, which claims the benefit under 35 U.S.C 119(e) of U.S.Provisional Application Ser. No. 60/437,537 filed Dec. 31, 2002.

TECHNICAL FIELD

This disclosure relates generally to self-contained energy sources, andmore particularly to method and apparatus for porous insulative film forinsulating energy source layers.

BACKGROUND

Energy storage components, such as batteries and capacitors, are used ina variety of electronic devices. As technology evolves, devices usingthese components consistently demand smaller component sizes. However,in meeting the demands of technology, these components cannot sacrificeperformance. As such, the art requires energy storage components whichare smaller, but which meet or exceed energy requirements.

In meeting these requirements, energy storage components have their ownrequirements, extending to manufacturing, use, and end of lifeperformance. Manufacturing requirements demand reliable and efficientassembly. Use requirements demand reliability and small package sizeshaving satisfactory power delivery. End of life requirements requirethat as the components age, they retain their operable characteristics.Within each of these phases is the demand that battery subcomponents arenot damaged by other battery subcomponents. Thus, what is needed are newenergy storage subcomponent designs which demonstrate improvedproperties with respect to manufacturing, use, and end of life, withoutdamaging other subcomponents.

SUMMARY

The above-mentioned problems and others not expressly discussed hereinare addressed by the present subject matter and will be understood byreading and studying this specification.

One embodiment of the present subject matter includes an apparatus,having: an anode having an elongate ribbon shape; a cathode having anelongate ribbon shape, the cathode disposed adjacent to and in alignmentwith the anode; a separator disposed between the anode and the cathode;and a first porous edge film disposed between a first edge of thecathode and the anode, with the one or more surfaces of the first porousedge film facing the cathode and defining a first cathode interface ofthe first porous edge film; wherein an first adhesive interconnects thefirst porous edge film to the cathode, the first adhesive covering lessthan the entire cathode interface, and the anode and cathode aredisposed in a case with an electrolyte.

Additionally, in one embodiment, the present subject matter includes anapparatus having an anode including alkali metal and having an elongateribbon shape; a cathode including metal oxide conformed to a wire meshsubstrate, the cathode having an elongate ribbon shape having a cathodewidth and an cathode length, the cathode length extending between afirst and second cathode edge, a separator including porous polymericmaterial disposed between the anode and the cathode; a first and secondporous edge film including porous polymeric materials, the first andsecond porous edge films respectively wrapped around the first andsecond cathode edges, with one or more surfaces of the first and secondporous edge films facing the cathode and defining a first and secondrespective cathode interface; a battery case having a first openingsized for passage of the anode, the cathode, the separator, and thefirst and second porous edge films, the battery case having afeedthrough and an electrolyte backfill port; a battery case lidsealably conformed to the first opening of the battery case; pulsegeneration electronics electrically connected to the anode and thecathode; and a hermetically sealed device housing having a devicehousing opening sized for passage of the battery case and the pulsegeneration electronics, with a housing lid sealably conformed to thedevice housing opening; wherein a pressure sensitive adhesiveinterconnects the first and second porous edge films to the cathodealong less than the entire first and second cathode interfaces, and theanode, cathode, separator and first and second porous edge films aredisposed in a jelly roll configuration in the battery case along withelectrolyte, with the battery case and the pulse generation electronicsdisposed in the hermetically sealed device housing.

One embodiment of the present subject matter includes an apparatus,having: an anode having an elongate ribbon shape; a cathode having anelongate ribbon shape, the cathode disposed adjacent to and in alignmentwith the anode; a separator disposed between the anode and the cathode;and an edge film means for insulating the edge of the cathode from theanode.

This Summary is an overview of some of the teachings of the presentapplication and not intended to be an exclusive or exhaustive treatmentof the present subject matter. Further details about the present subjectmatter are found in the detailed description and appended claims. Otheraspects will be apparent to persons skilled in the art upon reading andunderstanding the following detailed description and viewing thedrawings that form a part thereof, each of which are not to be taken ina limiting sense. The scope of the present invention is defined by theappended claims and their legal equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view including an anode and a cathode, according to oneembodiment of the present subject matter.

FIG. 2 is a partial side view taken at line “2” of FIG. 1, according toone embodiment of the present subject matter.

FIG. 3 is a partial side view taken at line “3” of FIG. 1, according toone embodiment of the present subject matter.

DETAILED DESCRIPTION

The following detailed description of the present subject matter refersto subject matter in the accompanying drawings which show, by way ofillustration, specific aspects and embodiments in which the presentsubject matter may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice thepresent subject matter. References to “an”, “one”, or “various”embodiments in this disclosure are not necessarily to the sameembodiment, and such references contemplate more than one embodiment.The following detailed description is demonstrative and not to be takenin a limiting sense. The scope of the present subject matter is definedby the appended claims, along with the full scope of legal equivalentsto which such claims are entitled.

Self-powered electronic devices are known. For example, implantablemedical devices are now in use for treating a variety of diseases. Someimplantable pulse generation devices, as well as other types ofimplantable medical devices, are powered by a battery contained withinthe housing of the device. Additional designs include, within thehousing of the device, a capacitor sized to deliver a pulse of aselected intensity and duration. Various designs couple batteries andcapacitors to achieve desired function. The present subject matter isrelated to batteries and capacitors for these devices.

Batteries within the scope of the present subject matter include varioussubcomponents. For example, various battery embodiments include opposinganode and cathode plates. Because of pressure to reduce battery size inorder to make electronic devices smaller, various configurations usingthese plates are employed. Some embodiments of the present subjectmatter use elongate ribbon shaped plates which are adjacent andparallel, and which are wound together lengthwise to form a roll. Platesare rolled for various reasons. One reason is to increase packagingefficiency. Another reason is to increase manufacturing efficiency.

Various embodiments utilize anode and cathode designs which requireseparators to electrically isolate the anode and the cathode. Someseparators, in various embodiments, include porous materials to promotethe spread of electrolyte to the anode and the cathode. In someembodiments, separators include additional features, such as an abilityto melt in response to thermal input, substantially canceling the porousnature of the separator. It is necessary to ensure that separators arenot damaged, as damaged separators will not function as designed.

Various embodiment of the present subject matter utilize ribbon shapedelectrodes which include edge features which can damage separators.These features can damage other components as well. In some embodiments,an electrode includes wire mesh substrate which has been excised from alarger portion of wire mesh. In some embodiments, along the excisededge(s), the wire mesh has sharp features. The present subject matterprovides a covering for positioning between these sharp features andadditional subcomponents, to protect those subcomponents. In oneembodiment of the present subject matter, the covering is wrapped aroundthe excised edge.

In various embodiments, the excised edge covering is a film. In someembodiments, the film is porous. In some electrochemical embodiments, aporous film is useful to promote the spread of electrolyte between theanode and the cathode. In various embodiments, the film additionally hasan adhesive which interconnects the film to the electrode. Someembodiments of the present subject matter use a non-porous adhesive. Insome of these embodiments, the adhesive is configured along the film ina pattern which covers less than the entire film. The present subjectmatter covers these embodiments, but is not limited to theseembodiments.

FIG. 1 is a top view including an anode and a cathode, according to oneembodiment of the present subject matter. The embodiment includes ananode layer 102, and a cathode layer 104. Also pictured is first edgefilm 106 and a second edge film 112. Additionally pictured in hiddenlines are adhesives 108A-B, 110A-B. The pictured embodiment issubstantially planar, having a planar anode 102 disposed along a planarcathode 104. Various embodiments, however, include anodes and cathodeswhich are wound together into a roll. For example, in one embodiment,the electrodes are wound in a direction extending from the first edgefilm 106 to the second edge film 112. Winding can benefit manufacturingprocesses by decreasing the time needed to create a small package sizepower cell.

Winding, in various embodiments, introduces a tension in the windingmaterials. This tension is the product of winding the roll tightly. Thistension has a tendency to push adjacent components together. Forexample, in a wound embodiment, first edge 114 of cathode 104 is pushedagainst anode 102. In various embodiments, the introduction of thistension, and the disposition of the first edge 114 against anode 102,requires provisions to improve design reliability such that first edge114 does not damages anode 102.

For example, in various embodiments, anode 102 and cathode 104 areseparated by a separator. In various embodiments the separatorsubstantially encapsulates the anode 102, but other designs are withinthe scope of the present subject matter. The present subject matterincludes, but is not limited to, separators illustrated in paragraphs0175-0179 of related and commonly assigned U.S. patent publication,“Batteries including a flat plat design,” U.S. Patent Publication No.2004/0127952, filed Feb. 7, 2003, incorporated herein by reference. Theseparator, in various embodiments, is disposed between the anode 102 andthe cathode 104 proximal first edge 114, and first edge 114 is pressedagainst the separator.

In various embodiments, cathodes have a wire mesh substrate. In some ofthese embodiments, the cathode 104 is excised from the wire meshsubstrate. In excising the cathode from the wire mesh substrate, variousembodiments create edges which have burrs. Additional edges have sharpfeatures which are not burrs, such as wire portions which protrude. Insome of these embodiments, the sharp features of the cathode edge 114are pushed against the separator. In the pictured example, sharpfeatures are limited to a first cathode edge 114 and a second cathodeedge 116, due, in part, to manufacturing processes which produce a stripof wire mesh which has edges extending lengthwise along the strip whichdo not have sharp features. In this process, the cathode 104 is excisedfrom the strip along edges 114 and 116. This process serves toillustration the present subject matter, but other configurations alsoexist within the scope of the present subject matter.

To reduce instances of separator damages from cathode edges 114, 116contacting a separator, various embodiments include edge films 106, 112.Edge films 106, 112, in various embodiments, include materials which areof increased toughness such that the films do not tear when contacted bya cathode edge 114. In additional embodiments, edge films 106, 112 havea thickness adapted to prevent damage. By disposing edge films 106, 112between cathode edges 114, 116, damage from the cathode can be limited.While the pictured embodiment uses edge films which do not extendcompletely along cathode edge 114, additional embodiments feature edgefilms which do. Still further embodiments provide edge films whichextend beyond the boundaries of cathode edge 114.

Damage extends to damaging separators, but also extends to other formsof damage, such as shorting, breakdown, or disruption of electrodematerials. For example, in some embodiments, the anode is comprised of apellet. High point loads against the pellet can encourage the pellet tolose its shape, in some embodiments. Additional embodiments have abrittle oxide coating which can be disrupted by areas of high stress.Edge films 106, 112 work to reduce these types of disruptions. Edgefilms 106, 112 also produce other features, including stability in useand during manufacturing. For example, edge films 106, 112 assist duringwinding of anode 102 and cathode 104, by providing a smooth surface forthose layers to traverse, without catching or snagging.

FIG. 2 is a partial side view taken at line “2” of FIG.1, according toone embodiment of the present subject matter. The illustration shows anedge film 106 wrapped around the edge 114 of cathode 104. Additionallyvisible is a cathode material 202 and a cathode substrate 204, to whichthe cathode material 202 is affixed. Anode 102 is additionally pictured.

The cathode material 202 can include a metal, a metal oxide, a mixedmetal oxide, a metal sulfide and carbonaceous materials. For example,various embodiments include carbon, fluorinated carbon, silver vanadiumoxide, copper silver vanadium oxide, copper vanadium oxide, manganesedioxide, cobalt oxide, nickel oxide, copper oxide, iron sulfide, irondisulfide and others. Additionally, various binder materials may be usedin cathode material 202, including fluoro-resin powders such aspolytetrafluoroethylene (PTFE) powder and materials having electronicconductive characteristics such as graphite and/or carbon black. In somecases, no binder material or electronic conductor material is used.These materials provide examples of cathodic materials, but the presentsubject matter is not so limited.

In various embodiments, cathode materials 202 are affixed to a substrate204. For example, in one embodiment, a cathode 104 is prepared by usingpressure to affix cathode materials 202 to a substrate 204. Thesubstrate 204, in various embodiments, functions as a current collector.Example substrates include titanium, stainless steel and nickel. Alloysincluding multiple examples of these elements are also possible.Terminal portions extending away from the substrate are also possible.

In various embodiments, the substrate 204 may have sharp featuresproximal edge 114. To prevent these features from contacting otherbattery components, edge film 106 is used, in various embodiments. Inthe pictured embodiment, the edge film 106 is wrapped around edge 114.In various embodiments, an anode overhang 206 may be wrapped around thecathode edge 114. In embodiments where an anode overhang 206 is wrappedaround the cathode edge 114, the positioning of the edge film 106 aroundedge 114 provides protection for the anode 102 from sharp featurespresent at cathode edge 114. However, in additional embodiments, theanode 102 and cathode 104 are not wrapped as such. Additionalembodiments include an edge film 106 which is disposed between the anode102 and the cathode 104 without wrapping around edge 114.

In various embodiments, the anode includes an alkaline metal, such aslithium. Various alloys which serve as anodes are within the scope ofthe present subject matter, including LiSi, LiAl, LiB, LiMg, LiAlMg, andLiSiB. These materials provide examples of anodic materials, but thepresent subject matter is not so limited.

Edge film 106, in various embodiments, is compatible with electrodechemical activity between anode 102 and cathode 104. For example, invarious embodiments, edge film 106 is chemically unreactive with anode102 and cathode 104. Additionally, in various embodiments, edge film 106is porous. For example, various embodiments include porosity sufficientto allow electrolyte to flow through the edge film 106, with theelectrolyte extending to the anode 102 and the cathode 104. Illustrativematerials for the edge film 106 include various polymers. Some edgefilms have microporous properties. Various films include polyethylenetetrafluoroethylene (PETFE). Some embodiments include polypropylenemembrane available under the brand name CELGARD, a product of CelgardLLC, of Charlotte, N.C. Additional embodiments include non-woven glassand glass fiber materials, woven glass fiber materials, polypropylene,polyethylene, microporous materials, ceramics, polytetrafluorethylenemembrane, polypropylene membrane, and woven separators havinghalogenated polymeric fibers. Although the edge film is shaped like athin sheet, additional embodiments having alternation shapes adapted fordisposition between an electrode edge and another electrode fall withinthe scope of the present subject matter.

FIG. 3 is a partial side view taken at line “3” of FIG. 1, according toone embodiment of the present subject matter. The illustration shows anedge film 106 wrapped around the edge 114 of cathode 104. Additionallyvisible is a cathode material 202 and a cathode substrate 204, to whichthe cathode material 202 is affixed. Anode 102 is additionally pictured.Additionally pictured is adhesive 108B.

In various embodiments, the present subject matter includes an adhesiveon at least one surface for the purpose of adhering the edge film to asurface. Although the illustration shows the edge film 106 wrappedaround a cathode edge 114, other embodiments are possible. The edge filmmay alternately be wrapped around an edge of an anode, for example. Theedge film may additionally be disposed between a cathode and an anodewithout wrapping.

In various embodiments, the adhesive 108B is a pressure sensitiveadhesive (PSA). In some embodiments, the PSA is covered by a releaseliner. In various embodiments, during the assembly of the edge film,prior to bonding the edge film to a surface, the PSA is applied to theedge film using a release liner. In additional embodiments, the PSA isapplied to a target surface, such as the cathode edge, using a releaseliner. The PSA may additionally be applied to the anode. The PSA doesnot necessarily have to wrap around an edge; embodiment disposing thePSA between the cathode and the anode at one of a cathode edge or ananode edge fall within the scope of the present subject matter. Invarious embodiments, the release liner is a paper or plastic filmmaterial having a release coating.

In one embodiment, a surface of the edge film facing a target surface iscovered by the adhesive, and the remainder of the edge film face isexposed. For example, in various embodiments, it is possible to trace apath across the surface of the edge film to which the adhesive isadhered, without encountering the adhesive. In some of theseembodiments, the path is a substantially straight line. In oneembodiment, in which the edge film is elongate and applied to the shortedge of an elongate ribbon shaped cathode, the path extends across theedge film such that it is substantially straight and substantiallyperpendicular to the length of the ribbon shaped cathode.

The organization of adhesive on the edge film as such is for severalreasons. In some battery embodiments, the adhesive is organized as suchso that lithium is depleted from the anode in a manner which does notshort or truncate the lithium electrode. For example, in variousembodiments, a sheet of cathode lies on a sheet of anode. In some ofthese embodiments, at least one edge film is disposed between at leastone cathode edge and the anode. If this edge film were nonporous, invarious embodiments, the lithium in the penumbra of the interfacebetween the anode and the edge film would deplete at a higher rate. Thisis because the potential between the anode portion defined by the edgefilm perimeter and the cathode portion defined by the edge filmperimeter remains, while the ion paths for that potential are all bentaround the edge film. As such, the penumbra of the edge film interfaceincludes more ion paths per unit of area than do other portions of thebattery not having a non-porous edge film. More ion paths mean fasterdepletion.

If the edge film extended across a width of the lithium sheet, thisdepletion would effectively truncate a portion of the lithium anode thatextended outside the perimeter of the cathode. To resist this behavior,various configurations use a porous edge film, a configuration which hasthe tendency of regularizing the rate of lithium depletion in areasproximal the edge film. But, to fulfill various manufacturing efficiencyneeds, in various embodiments edge film is be adhered to at least one ofthe anode and the cathode. In various embodiments, the adhesive isnonporous. This reintroduces the truncation problem, in variousembodiments.

As such, the present subject matter includes configurations which ensureone or more paths extend across the edge film which do not haveadhesive. By limiting the high-depletion rate areas of the anode to lessthan the entire width of the anode, various embodiments of the presentsubject matter reduce the tendency for truncation of a portion of theanode which extends outside the perimeter of the cathode. This reductionin truncation allows for improved end-of-life behavior of the battery.

Although the present example includes a film-type PSA, it should benoted that other embodiments fall within the scope of the presentsubject matter. Adhesives which have the tendency of adhering thecathode to the edge film, or the anode to the edge film, fall within thescope of the present subject matter. This includes spray-on adhesives.This additionally includes adhesives applied in striped patterns, inhalf-tone patterns, or in other patters. Additional types of patternsare within the scope of the present subject matter. Additional adhesiveapplication methods fall within the scope of the present subject matter.

Returning to the discussion of PSA, it is noted that various embodimentsmay be derived from a variety of known water-based, solvent-based, and100% solids hot melt adhesive compositions. In various embodiments,adhesive compositions are selected depending on the intended duration ofuse and expected exposure conditions of the edge film (e.g. temperature,humidity, sunlight, delamination). Transparent adhesive compositions,translucent and opaque adhesive compositions fall within the scope ofthe present subject matter. Colored adhesives additionally fall withinthe scope of the present subject matter. One type of adhesive iscommercially available from 3M Company, organized in St. Paul, Minn.,under the trade designation 200 MP.

In various embodiments, the present invention includes PSAs includingalkylacrylate polymers and copolymers; copolymers of alkylacrylates withacrylic acid; terpolymers of alkylacrylates, acrylic acid, andvinyl-lactates; alkyl vinyl ether polymers and copolymers;polyisoalkylenes; polyalkyldienes; alkyldiene-styrene copolymers;styrene-isoprene-styrene block copolymers; polydialkylsiloxanes;polyalkylphenylsiloxanes; natural rubbers; synthetic rubbers;chlorinated rubbers; latex crepe; rosin; cumarone resins; alkydpolymers; and polyacrylate esters and mixtures thereof. Additionally,the present subject matter includes polyisobutylenes, polybutadienes, orbutadiene-styrene copolymers, and mixtures thereof; silicone-basedcompounds such as polydimethylsiloxane, and polymethylphenylsiloxanecombined with other resins and/or oils. The present subject matterfurther includes terpolymers of ethyl acrylate, butyl acrylate, andacrylic acid; copolymers of isooctylacrylate and acrylamide; andterpolyrmers of isooctylacrylate, vinyl-acetate, and acrylic acid. Invarious embodiments, acrylic-based PSAs are coated by an organicsolvent, such as a heptane:isopropanol solvent mixture, which is laterevaporated. Additionally PSAs within the scope of the present subjectmatter include tackified thermoplastic resins and tackifiedthermoplastic elastomers, wherein the tackifier comprises one or morecompounds which increase the tack of the composition. While the presentsubject matter includes these materials, additional materials can beselected, and additional combinations of these materials fall within thescope of the present subject matter.

As such, a method within the scope of the present subject matterincludes applying an adhesive to a porous edge film in a pattern;applying the porous edge film to an edge of an elongate cathode having aribbon shape such that the adhesive adheres the porous edge film to theedge of the cathode, with the one or more surfaces of the porous edgefilm which face the cathode being partially covered by adhesive;disposing the cathode adjacent an anode having an elongate ribbon shape,with a separator disposed between the anode and the cathode, such thatthe porous edge film is disposed between the anode and the cathode; anddisposing the anode, the cathode, the separator, and the porous edgefilm in a case, with electrolyte disposed in the case. Some of thesemethods include rolling the anode and the cathode together.

APPLICATION

In various applications, the anode 102, cathode 104, along with anelectrolyte and associated components are assembled for use as an energysource. In various embodiments, the anode and cathode are woundtogether. In additional embodiments, they are otherwise folded together.In some embodiments, they are not wound. Various embodiments include astack of planar electrodes. Each of these embodiments is combined with arespective case for use. In various embodiments a case includes one ormore terminal feedthroughs for interconnecting electrodes to componentsseparate from the energy source. A case may be conductive, in variousembodiments. In some of these embodiments, the case is interconnectedwith electrodes, and is active. Various embodiments include within thecase an electrolyte. Some of these embodiments includes a backfill portfor filling the case with electrolyte.

In various embodiments, the energy source case is disposed in a devicehousing. The device, in various embodiments, includes a capacitor forproviding power for pulse generation. In various embodiments,electronics are disposed in the housing. In some embodiments, a battery,a capacitor, and electronics are disposed in a sealed housing adaptedfor implantation. The housing, in various embodiments, is hermeticallysealed. Some embodiments include interface features, such as sealedconnectors, for interconnecting the device to additional components. Inone embodiment, leads for disposition in vasculature are interconnectedto the device. Some embodiments use the leads in conjunction with thedevice housing to generate an electronic potential.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiment shown. This application isintended to cover adaptations or variations of the present subjectmatter. It is to be understood that the above description is intended tobe illustrative, and not restrictive. Combinations of the aboveembodiments, and other embodiments will be apparent to those of skill inthe art upon reviewing the above description. The scope of the presentsubject matter should be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled.

1. An apparatus, comprising: an anode having an elongate ribbon shape; acathode having an elongate ribbon shape, the cathode disposed adjacentto and in alignment with the anode; a separator disposed between theanode and the cathode; and a first porous edge film disposed between afirst edge of the cathode and the anode, with the one or more surfacesof the first porous edge film facing the cathode and defining a firstcathode interface of the first porous edge film; wherein a firstadhesive interconnects the first porous edge film to the cathode, thefirst adhesive covering less than the entire cathode interface, and theanode and cathode are disposed in a case with an electrolyte.
 2. Theapparatus of claim 1, wherein the first adhesive is a pressure sensitiveadhesive.
 3. The apparatus of claim 1, wherein the anode includes analkali metal.
 4. The apparatus of claim 1, wherein the cathode includesa metal oxide.
 5. The apparatus of claim 4, wherein the electrolyteincludes an organic compound.
 6. The apparatus of claim 1, wherein thefirst porous edge film includes polyethylene tetrafluoroethylene.
 7. Theapparatus of claim 6, wherein the first porous edge film has a porosityof approximately 55%.
 8. The apparatus of claim 1, where the anode andthe cathode are arranged in a jelly roll.
 9. The apparatus of claim 8,where the anode and the cathode are connected to respective terminalswhich are interconnected to pulse generation electronics, the pulsegeneration electronics and case disposed in an hermetically sealedimplantable device housing.
 10. The apparatus of claim 1, wherein thecathode has the shape of an elongate body extending lengthwise betweenthe first edge and a second edge, and the first porous edge film iswrapped around the first edge of the cathode.
 11. The apparatus of claim10, wherein the adhesive is striped along the first porous edge filmsuch that one or more areas of the first porous edge film are notcovered with the adhesive in a direction parallel a direction extendingbetween the first and second edge of the cathode.
 12. The apparatus ofclaim 1, further comprising a second porous edge film disposed between asecond edge of the cathode and the anode, with the one or more surfacesof the second porous edge film facing the cathode and defining a secondcathode interface of the second porous edge film.
 13. The apparatus ofclaim 12, wherein the second porous edge film is wrapped around a secondedge.
 14. The apparatus of claim 12, wherein a second adhesiveinterconnects the second porous edge film to the cathode, the secondadhesive covering less than the entire cathode interface.
 15. Anapparatus, comprising: an anode including alkali metal and having anelongate ribbon shape; a cathode including metal oxide conformed to awire mesh substrate, the cathode having an elongate ribbon shape havinga cathode width and an cathode length, the cathode length extendingbetween a first and second cathode edge, a separator including porouspolymeric material disposed between the anode and the cathode; a firstand second porous edge film including porous polymeric materials, thefirst and second porous edge films respectively wrapped around the firstand second cathode edges, with one or more surfaces of the first andsecond porous edge films facing the cathode and defining a first andsecond respective cathode interface; a battery case having a firstopening sized for passage of the anode, the cathode, the separator, andthe first and second porous edge films, the battery case having afeedthrough and an electrolyte backfill port; a battery case lidsealably conformed to the first opening of the battery case; pulsegeneration electronics electrically connected to the anode and thecathode; and a hermetically sealed device housing having a devicehousing opening sized for passage of the battery case and the pulsegeneration electronics, with a housing lid sealably conformed to thedevice housing opening; wherein a pressure sensitive adhesiveinterconnects the first and second porous edge films to the cathodealong less than the entire first and second cathode interfaces, and theanode, cathode, separator and first and second porous edge films aredisposed in a jelly roll configuration in the battery case along withelectrolyte, with the battery case and the pulse generation electronicsdisposed in the hermetically sealed device housing.
 16. The apparatus ofclaim 15, wherein the first porous edge film has a porosity ofapproximately 55%.
 17. The apparatus of claim 16, wherein the firstporous edge film includes polyethylenetetrafluoroethylene.
 18. Anapparatus, comprising: an anode having an elongate ribbon shape; acathode having an elongate ribbon shape, the cathode disposed adjacentto and in alignment with the anode; a separator disposed between theanode and the cathode; and an edge film means for insulating the edge ofthe cathode from the anode.
 19. The apparatus of claim 18, furthercomprising adhesive means for connecting the edge film means to thecathode.
 20. The apparatus of claim 18, further comprising pulsegeneration electronics connected to the anode and the cathode, the pulsegeneration electronics, anode, cathode, separator, and edge film meansdisposed in a hermetically sealed housing having a first opening sizedfor passage of the anode, the cathode, the separator, and the edge filmmeans, with a housing lid sealably conformed to the first opening.